FR2559885A1 - ELECTROMAGNETIC PUMPING SIDE BASIN FOR FOUNDRY OVEN - Google Patents

Abstract

The invention relates to a lateral basin for electromagnetic pumping in a foundry and in particular in a light metal foundry. The pump comprises a magnetic circuit (207) which is locally saturated and which is embedded in the ceramic of the said basin. The electrical excitation winding of the magnetic circuit (208) is located outside the basin, and the circuit is disposed to create a horizontal leakage field through an active portion (204) of a liquid metal turn which, together with electrical current induced in said active portion (204), sets up a magnetic pumping force which is upwardly directed and which urges liquid metal into a duct (206) leading away from the furnace to liquid metal receiving means. The liquid from the furnace (202) supplies the active portion of the liquid metal turn (204) via a passage (205) of height limited by a partition (209). The electromagnetic pumping basin enables almost any casting requirements in a foundry to be supplied with liquid metal.

Description

The present invention relates to a side pond electromagnetic pumping

  furnace tick intended to convey the metal in the liquid state only under the action of electromagnetic forces, to feed molds in the foundry industry in general, but more particularly in that of light metals. This use of electromagnetic forces is well known and has been the subject of numerous patents in electromagnetic pump applications.

  that we will classify into two categories.

  The first concerns pumps for liquid sodium for fast neutron nuclear reactors mainly. They are the subject of most of the patents awarded around the world on this subject. The first to our knowledge date from the beginning of the century and the first pump was built by Hartman in 1918. The main ones are the patents of Albert Einstein and Leo Szélard taken in Berlin around the 30s (Patent nr 555.413 Klasse 17a-group 304 and 476.812-Klasse 31c-group 26, for example). Sodium circulates always protected from the air in a duct generally low carbon stainless steel and the active part of the pump is built around this duct,

  magnetic part and electric windings being in the open air.

  They are therefore mentioned here for the sake of remembrance but are of a very different construction and use mode from our application, although

  same electromagnetic principles to convey the metal.

  The second concerns pumps for industrial melted metals other

  than sodium. They use technologies comparable to those of ovens.

  These are pumps marketed at UoS.A. by M and T Manufactoring Co. of Grand Rapid and subject to U.S. Patent No. 3,931,960. They use the principle of the law of Lentz to raise the metal of the liquid coil around a single parallelepiped magnetic core provided with a coil and

  protected from metal by ceramic. These pumps are close to those corresponding to

  laying down the German patent of Florens and Coester n 837.579-Klasse 21hgruppe

  25 of July 8, 1949. These pumps are used for the mixing of metal in

  aluminum furnaces to accelerate the melting of the metal. This is the only application we know and advertising or literature speak only of this application because the metal can be raised only a very low height in principle. Flow, however, can be as important as

  desired, which is favorable in the brewing action of the metal.

  Other electromagnetic pumps were made by GAAA, later renamed Société Novatome. We will quote the following French patents: GAAA 71-09159 filed on 16.03.1971 71-11143 filed on 30.03. 1971 71-11372 filed on 31.03.1971

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  Novatome 79-14.585 filed on 7.06.1979 81-02.099 filed on 4.02.1981 These pumps, marketed, work well but to be able to use them you need an oven with a suitable basin except perhaps those corresponding to the latest patents Novatome which are much smaller and fit into small basins. But then the magnetic circuits inside the ceramic are reduced in size by the dimensions of the pump and therefore limit its performance. Finally for these pumps, it is difficult to clean the inner conduit because the internal thickness of ceramic protecting the magnetic circuits is low if one wants to have some performance. Therefore this ceramic thickness in the air gap is fragile and may be broken

  during a slightly active cleaning of the internal liquid vein.

  On the other hand, the pump being placed in an open basin next to the smelter, it has a tendency to treat the metal in this basin to refine it. But in this case the pump will be more or less quickly put out of use following the

staff care.

  Apart from these pumps, there are electromagnetic furnaces with inductive

  whose active part is always located outside the oven.

  Among the patents having inductors below the oven, we will mention the following in France: - National Smelting n 949.066 filed July 7, 1947 which corresponds to the well known Ajax ovens. In a variant the inductor is placed under a basin with

  the electric part below the oven.

  - Polischuck No. 1,600,320 filed December 31, 1968.

  - Edmond Ventre for E.D.F. No 74.23516 filed July 5, 1974.

  There are also furnaces where the metal is conveyed to the outside by bottlenecks.

  or tubes surrounded wholly or partly by electronic systems.

  Magnetic located outside on the side of the oven.

  These are the following French patents: - Inge Sundberg for ASEA n 70. 16,984 filed on May 11, 1970 - by Alex Von Starck for AEG-Elotherm n 70. 24,712 filed on 03.07.1970 All these furnaces have the disadvantage of circulate the metal in ducts or chutes out of the oven. In case of break below the level of

  bath, the leakage of the metal, by this rupture, would be detrimental to the electrical

  but also for the surrounding material.

  To counter all these defects, Morin in his American patent n 2.224. 982

  December 17, 1940, used to pump metal into the furnace an electric winding

  tromagnetic induction immersed in the oven at an angle. This system of fully immersed coils is not easy to use because the temperatures at which the coils are worn are very high. We know that we always have interest to postpone them outside the bath. On the other hand, if one is obliged to immerse them, one has interest in cooling them by an external fluid. But this leads to extracting calories from the liquid bath and the oven must then compensate for these thermal losses.

by a supplement of heating.

  The invention consists in incorporating inside the lateral basin of an oven the magnetic elements and the liquid coil intended for pumping by integrating them into the furnace ceramic and to transfer the outside of the basin into the ambient air

  the electrical windings necessary for pumping.

  There is no longer any fear of external metal leakage since it is the internal ceramic of the furnace that surrounds the magnetic circuits and protects them from the highly corrosive liquid metal at these temperatures. This ceramic is usually

  contained inside a metal tank which most of the time is itself

  even waterproof. The role of this sealed tank is also to protect mechanically

  oven ceramics during transport or shocks on site.

  One can thus integrate in this basin one or more known electromagnetic pumping systems. But in the application envisaged,

  will use more particularly an original pumping system.

  To facilitate the understanding of the functioning of this original system

  proposed, we will break down the different phases through which the invention

  to arrive at the proposed solution, each step being a pos-

  sibility of use, but all based on the use of a magnetic circuit

partially saturated.

  In Figure 1, we describe the basic principle which is a transformer with a primary coil 1 and a secondary coil 2 full of liquid metal, open on the furnace on the front face of the coil. The magnetic circuit of the transformer 3 is deformed in the lower part by partial approximation of one or vertical legs, which will allow the passage of a vanishing field

  horizontal, from the left leg 4 to the right leg 5 of this transfor-

  in the near part, the lower horizontal leg 7 being

  partially short-circuited by the leakage field.

  It is possible to increase this horizontal leakage field between the two vertical legs partially close to the transformer by creating a

  local saturation by one of the well known means, such as for example a

  che 6 in a right leg 5 as shown in Figure 1. But this could equally well be obtained by vertical or horizontal slots or holes inside the magnetic circuits or by progressive shrinkage of these vertical legs, or the horizontal branch, or by partial replacement of sheets, magnetic at these operating temperatures, by non-magnetic or less magnetic sheets or by other means

known.

  This saturation creates, therefore, just above the shrinkage 6 of the magnetic circuit, the horizontal leakage field HI, which does not pass through the lower horizontal beam and passes from one end of the transformer to the other. above

saturation.

  This combined RF leakage field Xe ((the secondary current Is induced in the liquid coil 2 creates a vertical force Q pumping by application of

  the law of Laplace, called the law of Aimpère for the Xenglonians.

  In practice this electromagnetic pumping system dot the theory has just been described above is poured into the ceramic of the lateral bass of a

  foundry furnace as shown in Figures 2, 3 and 4.

  In Figure 2 we have, from left to right, the charge bass

  101, the melting basin or meister 102 and the elements I electric heating 103. But of course, without changing anything to the invention, the oven could

  be heated by gas, fuel or a system induttion. The system

  electromagnetic pumping system is on the right side of the oven in the side basin. We find in this bassmin the liquid coil 10J4 in connection with the furnace by the inlet port 105 and connected to the outside by the conduit 106. The magnetic circuit 107 is fed by the coil 108. We will notice that opposite the active vein of the liquid coil 104 a ceramic partition 109 separates the active vein 104 from the furnace 102 to thereby limit the parasitic circulation of the liquid metal between the oven and active vein. Thus this active vein of the turn 10 4 is at an altitude higher than the bottom of the oven and the turn 104 is inclined down to this melt of the oven which allows the emptying of

the spire.

  In FIG. 3, which is the vertical section of the pelvis at the level of the electromagnetic pumping system, we find the liquid vein 104 and we also note that the entry vein on the right is: at a lower altitude, which reads the active vein. There is also the magnetic circuit 107 and the excitation coil

  108. The saturation notch 110 in the magnet circuit is

presented in this figure 3.

  In FIG. 4, which is a horizontal section of the lateral basin at the level of the turn 104, magnetic circuit 107, the outlet tube 106 and the ceramic partition 109 partially separating the liquid coil 104 of FIG.

oven 102.

  The magnetic saturation electromagnetic pumping system represents

  schematically in Figure I is not limiting. For exemple

  we will give some variants of these electronic pumping systems

  Magnetic saturation magnet which can be placed under the ceramic of the lateral basin of the furnace, instead of the electrornagnetic pumping system

of Figure 1.

  One of these variants shown in FIG. 5 consists in using a transformer with three vertical magnetic arms with the median leg 54 passing in the center of the liquid coil 52. The current in this liquid coil is induced on the one hand by the circuit vertical leg 57 plus median leg 54 and partially by the vertical leg circuit 53 plus median leg 54. In this last circuit 53-54, the coil 58 will also serve to create the increased leakage field by the saturation notch 56 between the leg vertical 54 and the near part 55 of the

  53. The two reels 51 and 58 can be replaced on the horizontal branches

  upper tales by a single coil on the central leg 54 without changing anything

to the problem.

  Another variant, represented in FIG. 6, consists in using a transformation

  three vertical magnetic legger with extreme legs locally

  close together to create a pump with two liquid turns superimposed in series.

  The two diagrams of Laplace's law show that pumping forces

add.

  Similarly another embodiment, shown in Figure 7, is to use the same transformer with three legs extreme legs close to the median leg to create a parallel effects pump in the single turn. Each half turn is active and rejects the metal upwards. Both outputs can

  be independent or connected to have the parallel effect that increases throughput.

  Here we have shown, in Figure 7, the single coil on the median leg.

  It is likewise possible to use in the same spirit as shown in FIG. 8 a simple transformer with an excitation coil 81 and two vertical legs 83 and 84 with a turn 82 and 87 around each vertical leg between which the common part 88 of these two turns 82 and 87. The front face of these two turns 82 and 87 and the common part 88 are open on the main basin of the furnace which allows their supply of liquid metal. The common part 88 between the close parts of the legs

  verticals 83 and 84 will constitute the active vein of our electromagnetic system.

  tick. In this active vein 88, the currents induced in the two turns 82 and 87 are added in value and in direction. The saturation notch 86 placed

  here on the lower horizontal branch 89 increases the leakage field Hf.

  We have represented the diagram of Laplace's law and the direction of pumping

Q is also headed up.

  We recall that the saturation notch 86 can be replaced for example by a progressive narrowing of the two parts close together of the two

  vertical legs 83 and 84, or by the narrowing of the horizontal limb

  bottom 89 or by other known means such as slots or holes, etc.

  This description of the examples of using local saturation for

  Electromagnetic pumping systems are obviously not limiting since, of course, other applications within the scope of the invention derive from those of ordinary skill in the art, such as, for example, transformers.

  multi-legged with multiple turns with parallel effects or multiple series

  several floors. In practice, the lateral basin of a foundry furnace can be realized with the electromagnetic pumping system, the principle of which has been represented

  in Figure 8, placed in the ceramic of said side basin.

  In Figure 9 for simplicity, we have not not represented the entire oven, but only a small portion attached to the side basin which is the subject of the invention. The magnetic circuit 207 is partially embedded in

  the ceramic with the active coil 204 and the metal outlet duct 206.

  The excitation coil 208 is in the ambient air. The active coil 204 is connected with the furnace 202 by the inlet orifice of the metal 205. This active coil, which is shown in the figure, because of the section shown, only the active vein 204 and the front and back of the two turns connected to this active vein 204, is at a higher level at the bottom of the oven and the partition 209 goes down

  below the lower level of this turn to limit para-

  liquid metal sites between the active vein 204 and the furnace 202 through the orifice

205.

  In Figure 10 which is a vertical section of the basin by the axis of the magnetic circuit, we find the magnetic circuit 207 of the transformer with

  its excitation coil 208. The active vein 204 is located between the

  Vertical saturation of the transformer 207. The saturation is obtained here by the progressive narrowing 210 of the close portions of the vertical legs. The two turns 211 and 212 with the common part 204 surround these closely spaced portions 210 of the vertical legs and are in connection with the furnace. The turns 211 and 212 have a progressively increasing altitude from the bottom level of the oven at the inlet 205 to the level of the active vein 204

  at the rear, which allows the emptying of all the liquid turns.

  The coil 208 is shown here above the basin of the oven but it can also be placed on the side on the front of the basin for example. In this case, the outlet tube 206 instead of being inclined could be vertical above the active vein 204 which would allow a connected outlet pipe

  tube 206 to have any orientation.

  We can even split the coil 208 to clear the top of the basin

  and placing the two coils on each side of the furnace without departing from the invention.

  In FIG. 11, which is a horizontal section at the height of the active vein, to facilitate understanding, we find the magnetic circuit 207 of the transformer, the active vein 204 with the two turns 211 and 212, the partition 239 and its outlet tube 206 represented in dotted line. he is at a disadvantage

with the DIan of: a cut.

  In Figure 12: we have represent, another variant do (oiislid tun

  which involves premolding the electromagnetic pumping system (oilprendnt.

  At least part of the magnet circuit 307 and at least a portion of the liquid coil 304 in a ceramic block 313 is identical to that of the basin or different. The lateral pelvis is aniosthe 315 and the ceranic 324 of lateral pelvis 315 is cast with an inner form to receive the shape

  313 of the ceramic block comprising the electronic pumping system

  ragneétique. We will put between the ceramics of the basin and that of the electronic system.

  and a flexible sheet of fiber or alumina felt of the trade which will facilitate disassembly and avoid the progression of a possible leak

I was liquid.

  The fixed part of the furnace 316 is fixed on a frame 317 which can receive the removable basin 315. The assembly of the removable basin on the oven is carried out by an ordinary screw-nut system 318 each compressing at least one spring whose role is to press another fiber seal or alumina felt 319 placed

  between the removable basin 315 and the oven 316.

  In Figure 13, the furnace, shown assembled and seen from above, is 2S ceramic removable crucible. The crucible is heated by. example by electric sticks or by a set of expanded metal wedding

  the outer form of the crucible or embedded in fibers or the ceramic furnace.

  Figure 14 shows the different parts of the oven disassembled.

  We have given the oven represented a rectangular shape, but of course, we can give the whole electromagnetic furnace-basin all desirable shape to adapt to the needs of users. In particular, an oven

  cylindrical form fits perfectly within the scope of this invention.

  Likewise, the fact of using on the same oven several water basins

  Magnetic or several electromagnetic systems per basin, does not come out more of the scope of this invention 'oven with integrated electromagnetic basin side. Of course, it goes without saying that such furnaces can be used for all foundry applications: shell, low pressure, die casting machines. Foundry carousels. vacuum casting with sealed furnace, casting

  wax -pedue etc ... Indeed, such towers replace the electronic furnaces

  magnetic or pressurized ovens or even the smelter, to cast the metal Dar gravity or back in ir outlet tube to a, noule placed more

  Or even transfer it to the outside of the oven.

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Claims (6)

  1. Foundry furnace lateral basin characterized in that it is equipped with an electromagnetic pumping system including electric excitation coils   are released into the ambient air and that at least part of the magnetic circuit   and at least one of the liquid metal veins for pumping are housed in the ceramic of said basin.   2. Pond according to claim 1, characterized in that the magnetic circuit   tick has a magnetically saturated portion.   3. Basin according to claim 2 characterized in that the saturated part of the magnetic circuit is located at a local approximation of the vertical branches of the magnetic circuit, thereby developing between said branches a magnetic leakage field through one to less metal veins   liquid traversed by an induced electric current.   4. Pond according to claim 3, characterized in that the electronic system   Magnetic pump uses two contiguous secondary liquid turns, whose central common part forming the active vein, placed between the locally close branches of a magnetic circuit supply with local saturation is crossed by the electromagnetic leakage field between the vertical branches of the magnetic circuit and that this leakage field combined with the current   Induced in the active liquid vein creates the pumping force of the liquid metal.   5. Pool according to claims 1, 2, 3 and 4 characterized in that the said basin is removable.   Basin according to claims 1, 2 and 3 characterized in that at least   a part of the active magnetic circuits of the electromagnetic system and at least one of the liquid metal veins are housed in a ceramic block   premoulée itself housed in the ceramic furnace to be dismantled.